Bob Woodward, who wrote two books praising President Bush and then a third harshly criticizing him, is out with a fourth tome that renders a mixed verdict on Bush, lauding the president’s surge of troops into Iraq, but saying "too often he failed to lead."

At 487 pages, "The War Within" is the fourth installment in Woodward’s series of books on the president. Its release is embargoed until Monday, although an advance copy was obtained exclusively by FOX News.

The new book is less critical than Woodward’s last tome, "State of Denial," which savaged Bush for his execution of the war in Iraq. "Denial" ended with the line: "With all Bush’s upbeat talk and optimism, he had not told the American public the truth about what Iraq had become."

Woodward repeats the line in his new book, adding: "My reporting for this book showed that to be even more the case than I could have imagined."

Bush refused to grant an interview to Woodward for "Denial," but gave the author several interviews for "War Within." Such increased access did not seem to improve Woodward’s opinion of Bush.

"President Bush has rarely leveled with the public to explain what he was doing and what should be expected," wrote Woodward, an assistant managing editor at the Washington Post, in "War Within." "He did not seek sacrifice from most of the country when he had the chance. He did not even mobilize his own party. Republicans often voiced as much suspicion and distrust as Democrats. The president was rarely the voice of realism on the Iraq war."

On the other hand, Woodward acknowledged the success of Bush’s surge of additional troops into Iraq in 2007.

"Violence was down so much in a few places that some U.S. soldiers were not receiving combat action badges because there was no fighting in their area," he wrote.

Woodward notes that Democratic presidential candidate Barack Obama opposed the surge, while GOP presidential candidate John McCain was “advocating more troops for years.” Woodward also quotes McCain expressing frustration with the Bush White House, clenching his fists in the West Wing and exclaiming to Woodward: “Everything is f---ing spin.”

Woodward asserts in his new book that Gen. George Casey, when he was the U.S. commander in Iraq, believed "that President Bush does not understand the war" and eventually concluded "he has lost the president’s confidence."

Calling Bush "the nation’s most divisive figure," Woodward criticized the president for failing to fulfill what some might view as impossible expectations.

"He had not rooted out terror wherever it existed," Woodward scolded. "He had not achieved world peace. He had not attained victory in his two wars."

Woodward also observed that seven years in the White House has "taken a visible toll" on Bush, who "has a noticeable paunch and sometimes slouches in his chair."